Roll deflection



March 26, 1963 L. A. MOORE ROLL DEFLECTION Filed March 8, 1961 INVENTOR.Lawrence 14({718/06 Moore BY 7 WWI, ZfMEORN/EYS United States Patent.Ofiice 3,082,685 Patented Mar. 26, 1963 3,082,685 RGLL DEFLECTIONLawrence A. Moore, Beloit, Wis., assignor to Beloit Iron Works, Beloit,Wis., a corporation of Wisconsin Filed Mar. 8, 1961, Ser. No. 94,262 8Claims. (Cl. 100-155) This invention relates to apparatus for mounting aroll whose axis is subject to deflection, and more particularly,

to an apparatus for mounting a roll that is subjected to a load tendingto eifect central deflection of the roll axis.

Although the instant invention may be useful in a number of arts, it isparticularly useful in the paper making art and will be describedprimarily in connection therewith. In paper machines there are a numberof different types of rolls of substantial size which are subjected toloads tending to deflect such rolls centrally. For example, wire returnrolls in a Fourdrinier paper machine are subject to a load tending toeffect central deflection thereof by virtue of the weight of the rollsthemselves and of the Fourdrinier wire carried by the rolls, the tensionon the Fourdrinier Wire, and, in the case of a driven roll, the forcecomponent resulting from the resistance or reaction of the wire itselfto the driving force. These forces tend to deflect the roll downwardlyin the middle and this results in an undesirable guidance of thetraveling Wire,

which it has been found advantageous to avoid by counteracting thetendency for downward deflection of the return roll in one manner oranother.

In addition, in pressv couples, calender stacks, etc. the web passesthrough a nip between a pair of superimposed rolls Whereat the web issubjected to pressures, The pressures thus applied at such nip tend toload the lower roll and deflect the same centrally downwardly. Suchdeflection results in an undesirable application of forces across thenip and other undesirable operating features; and such deflection isoften corrected in paper machines by crowning of the lower roll. Thecrowning of the roll requires accurate and expensive finishing of theroll surface so as to obtain a slightly greater roll diameter in thecentral portion of the roll; but such crowning is carried out on thebasis of a predetermined set of force conditions and may not besatisfactory for operation under a different set of force conditions.Accordingly, crowning of rolls often does not afiord satisfactoryoperation for many different types of operating conditions.

In other arts relating to paper machines, such as the coating of paperor fabrics with plastic materials, pressure or calender rolls are alsoused. Also, paint mixing roll systems or the like are subject to thebuildup of forces in the central portion of pressure nips which tend tocause central deflection of the rolls and result in nonuniform and/ orother undesirable conditions across the width of such press nips.

The instant invention affords a simple but unique mounting arrangementfor a roll subject to a load tending to cause deflection of its axis.One aspect of the instant invention involves the use of force couplesapplied through allochiral pairs of bearings mounting a roll, Le, aright hand pair and a left hand pair of bearings rotatably receivingstub shaft elements at opposite ends of the roll (or looking in themachine direction, at opposite sides of the roll). These pairs ofbearings are referredto herein as allochira for the reason that they areopposed right and left hand assemblies although not entirely symmetricalin every detail. The use of a pair of bearings to rotatably receive ashaft at one end of a roll for the purpose of applying a force couplethereto, wherein one of the bearings is fixed and the other movable, isshown in the prior art, for example, in Goulding US. Patent No.2,611,150.

In the instant invention, however, both of each pair of hearings in theassembly used to apply a force couple to the shaft are bearings fixedwith respect to each other but carried in a housing that is movable (ascontrasted to rigid assembly of one of the hearings in for example astationary frame). Each of the allochiral pairs of bearings, and thehousing therefor, is in rigid connection with a lever arm extendingtherefrom to terminate adjacent the other of said pairs of bearings.Each bearing housing is pivotally mounted for a rocking type of movementrequired to exert the force couple, and the lever arm rigid with suchhousing is used to effect this rocking movement. A particular advantageof the instant invention resides in the extension of the lever arm fromthe housing rigid therewith at one end of the roll to the opposite endof such roll, for the reason that this extension of the lever armprovides a distinct mechanical advantage in the application of the verygreat forces required for the force couple. This positioning of thelever arm also 'makes possible an excellent weight and positionalarrangement for delicate control. The extension of the terminal Iportion of the lever arm beneath the roll and to the opposite sidethereof makes possible the mounting of the actuating or positioningmeans for the terminal portion of the lever arm completely outside theeffective operating area of the roll. The actuation of such lever arm(which is ordinarily done by a generally vertically aligned actuator atthe terminal portion thereof) also does not involve the application ofan end thrust to the bearings applying the force couple.

The force arrangement thus employed results in the application of forcecouples to the shaft elements tending to bow or deflect the roll in thedesired direction, which is generally opposite to the direction ofapplication of the "load. The exact contour which the axis of the rollwill take depends, of course, upon the relative strength of the roll andthe load applied thereto; but in accordance with the instant inventionit also depends upon the force couples applied at the shafts at oppositeends of the roll. In the present force arrangement, the force couple isapplied via the lever arm (which does not carry the weight of the roll)and the weight of the roll is carried via pivot means associated witheach of the bearing housings at opposite ends of the roll.

It is, therefore, an important object of the instant invention toprovide an improved assembly for mounting a roll subject to a load.

It is another object of the instant invention to provide an improvedroll assembly wherein force couples are ap- 'plied via shaft elements atthe ends of a roll subject to load in a predetermined manner whichaffords delicate and accurate application of the force couples byactuating means remote from the operating area of the roll itself.

Yet another object of the instant invention is to provide, in a mountingfor a roll whose centroidal axis is subject to deflection (said rollhaving shaft elements at opposite-ends thereof), in combination,allochiral pairs of bearings rotatably receiving said shaft elements andadapted to apply a force couple thereto, fixed pivots mounting each ofsaid pairs of bearings, allochiral lever arms rigid with each of saidpairs of bearings and extending therefrom to terminate adjacent theother of said pairs of bearings, and means for acting on the terminalportions of each of said lever arms to apply such force couple to saidshaft elements.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed disclosure thereof and the drawings attached heretoand made a part hereof.

On the drawings:

FIGURE 1 is a diagrammatic illustration showing the two lower rolls of astack of rolls, illustrating in exaggerated form the manner in whichsuch rolls may be defiected during specific correlation among theessential control factors in a calender stack of the prior art;

FIGURE 2 is a diagrammatic illustration similar to FIGURE 1, but showingmounting means of the invention for a roll subjected to a load tendingto cause deflection;

FIGURE 3 is an end elevational view taken substantially from the righthand side of FIGURE 2; and

FIGURE 4 is a top sectional view taken along the line IVIV of FIGURE 2.

As shown on the drawings:

In FIGURE 1, a bottom portion of a calender stack, indicated generallyby the reference numeral 10, is shown comprising a king roll 11 at thebottom mounted on suitable bearings 12 and 13 which are in turn firmlysecured to a fixed mounting such as a floor F. Immediately above theking roll 11 is a calender roll 14 which, in turn, is mounted forrotation in bearings 15 and 16. Actually, the roll 11 is provided with aleft hand stub shaft 11a or shaft element which is rotatably received bythe left hand bearing 12 and a right hand stub shaft 11b which isrotatably received by the right hand bearing '13. The roll 14 is alsoprovided with a left hand stub shaft 14a rotatably received by the lefthand bearing 15 and a right hand stub shaft 14b rotatably received bythe right hand bearing 16.

As will be noted, the axis X-11 for the roll 11 is defiected downwardlybelow a horizontal or center line C-ll at'the middle of the roll 11 andthis is caused by the load applied to the roll 11 by the weight of theroll 14 (and any other rolls thereabove). This weight is transmittedthrough the sheet of paper (shown in exaggerated thickness at W-l)passing through the nip between the rolls 11 and 14. In the calender 10,however, the central portion of the top surface of the roll 11 is stillcrowned so as to extend a distance R-ll above the outer extremities ofthe roll 11, and the bottom surface of the roll 11 is downwardly bowedstill a greater distance D11. The amount of operating crown R-ll dependsupon the amount of original crown formed on the roll 11 and the totalweight of the calender stack of rolls 14, etc. mounted thereabove. Aswill be appreciated, if it is desired to operate a calender withsubstantially no operating crown (R-ll') in the king roll 11, theinitial crown of the king roll 11' and the total weight of the calenderrolls 14, etc. are correlated so as to obtain substantially no operatingcrown. If, however, it then becomes desirable to make a change in theoperation of the prior art calender by using less calender rolls in thestack, then a greater operating crown R-ll will be obtained. This maypossibly result in an undesirable pressure distribution at the portionof the web W-l passing through the nip N-1. The same is true withrespect to variations in load which may be applied to any other crownedroll in a paper machine or other device.

In many of such prior art devices, the crown initially formed on theroll being subjected to the load is just sufficient to permit the rollto deflect in response to this predetermined load to such an extent thatthe roll presents a substantially flat (usually horizontal) nip definingsurface. It will be appreciated that any variation from suchpredetermined load will, however, necessarily result in a deviation fromthe desired flat or level contour of the operating surface or nipdefining line of the roll (herein designated 11c).

Referring now to FIGURE 2, it will be seen that the apparatus of theinstant invention is adapted to mount a roll 21 whose centroidal axis inthe unloaded condition of the roll; (C -21) is subject to deflection. Aswill be appreciated, the extent of deflection and crown has been greatlyexaggerated in FIGURE 1 and will also be exaggerated in the descriptionof FIGURE 2 for the purpose of simplifying the nature of the disclosure.As indicated diagrammatically in FIGURE 2, the axis (3-21 is a centerline for the roll 21 which would be a substantially straight, horizontalline in the view of FIG- URE 2, if the roll 21 were not subjected to anyloading forces including the load of its own weight. The roll 21 is,however, subjected to a load across its entire width, including the loadof its weight and the load applied by an upper roll (shown partially at24 in FIGURE 3 and represented in FIGURE 2 diagrammatically by arrows24a and 24b at the quarter points and 240 at the center of the roll,although such load 24a, b, c is actually applied uniformly across theentire width of the roll 21). As indicated in FIGURE 3, a paper web W-2traveling along the surface of the upper roll 24 (shown fragmentarily)passes downwardly and into a nip N-2 between the rolls 21 and 24 andthen outwardly from the nip N-2.

As shown in FIGURE 2, the roll 21 has shaft elements or stub shafts 21aand 21b at opposite ends thereof. Alloohiral pairs of bearings (showndiagrammatically as axially spaced bearings 22a, b as the left hand pairand 23a, b as the right hand pair) rotatably receive the stub shafts 21aand 21b respectively. The right hand pair of bearings 23a, 23b rotatablyreceives the stub shaft 21b, with the bearings 23a and 23b spaced fromeach other so that they are adapted to apply a force couple in agenerally vertical plane of the roll axis 021 and the load 24a, b, c(such couple being represented diagrammatically above the bearings 23a,23b as FC-l). The bearings 23a and 23b are securely mounted in aconventional housing 23, so that the bearings 23a and 23b will maintaina predetermined spaced relationship. The bearings 22a and 2212 are,likewise, mounted in a housing 22. A lever arm 25 that is rigidlyconnected to the housing 23 (which in turn is rigidly connected to thebearings 23a, 23b) extends from the housing 23 and the bearings 23a, 23bdownwardly at 25a and then inwardly from the right hand end of the roll21 and beneath the roll 21 at 25b the full width of the roll 21 toterminate, at 250 in the region of the opposite pair of bearings 22a,22b, and preferably beyond the left hand extremity of the roll 21.

The housing 23 is pivotally mounted, on a fixed pivot P, for limitedrocking movement. The pivot P is preferably positioned intermediate thebearings 23:; and 23b. A left hand fixed pivot P carries the housing 22and the bearings 22a and 22b rigid therewith in like manner. The pivot Pand P carries substantially the entire weight of the roll 21, thebearings 22a, b and 23a, b and the load 24a, b, c.

As is apparent from FIGURE 2, the left hand pair of bearings 22a, 22bare mounted in a substantially symmetrical assembly wherein partscorresponding to the right hand mounting assembly are designated by theprime of the same reference numeral.

The terminal portion 250 of the lever 25' is equipped with means foracting thereon to apply the force couple FC-l to the shaft element 21b.The means provided herein is a fluid pressure actuated diaphragm 26mounted on a fixed supporting surface S. The diaphragm 26 is adapted forlimited vertical movement of the lever terminal portion 256. The righthand lever terminal portion 250 is also equipped with a fluid pressureactuated diaphragm 26 which functions in like manner. The diaphragms 26,26 are conveniently located away from the operating area of the roll 21(which will be primarily the peripheral surface thereof and the regionimmediately above and below). In addition, the length of the lever armportions 25b and 25b is very substantial so as to provide the mostfavorable mechanical advantage for the operation of the levers 25, 25'so as to permit extremely delicate control of the application of boththe right hand force couple (PC-1) and the left hand force coupleUFO-2). The force couples (FC-l, 2) are shown diagrammatically toindicate the manner in which the force couples are applied tocorresponding stub shafts 21a, 21b

when an upward force is applied to the terminal lever portions 250, 25'sby the diaphragms 26, 26'. This results in a substantial straighteningout of the roll 21.

As will be appreciated, in the absence of such straightening out efiiectthe centroidal axis of the roll 21 would deflect centrally under theweight of the roll 21 and the load 24 along a dot-dash line B21 shown todeviate from the theoretical center line C-21 in greatly exaggeratedmanner in FIGURE 2. In actual practice, such a deviation from the centerline C-21 is very small numerically, but the effect thereof may be quitesignificant. Among other things, it may cause the presentation of anon-horizontal top surface 21c for the roll 21.

In the practice of the instant invention, however, it is possible tocorrect the normal tendency of the roll 21 to deflect so as to obtain acentroidal axis indicated in dash lines at A-21 (but also deviating ingreatly exaggerated manner from the theoretical center line C-21). Theapplication of the force couple FC-l of the right hand side will tend todeflect the center line A-21 slightly upwardly along the right handside, here indicated at approximately the quarter point 24b. Theopposite couple FC-2 tends to deflect the center line A-21 slightlyupwardly at the left hand side, here indicated at approximately thequarter point 24a. The unsupported center of the roll 21 will respond tothe load 24 much like a normal beam and will deflect centrallydownwardly slightly (at 240). This configuration A-21 is, however,substantially straight for practical purposes (and much more straightthan the normal beam deflection line B-21); and it involves a minimumaverage deviation from the theoretical center line C-21.

It will be appreciated that under certain preferred conditions it may bepossible to adjust the diaphragms (26, 26) so as to obtain what may bean ideal configuration for certain paper machine uses in the form of theaxis configuration A-21. In other instances, it may be desirable toimpart an overall crown to the upper surface 21c of the roll 21, andthis can be done by applying difierent forces through the force couplesand using different load combinations on the roll 21. Also, should it bedesirable to bow the operating surface 21c downwardly for the roll 21,this can be done by applying reverse forces to the bearing couples 22a,b and 23a, b. A particular advantage of the instant invention resides inthe delicate control which is permitted by the use of the present leverarm arrangement with improved mechanical advantage. Another improvedfeature of the invention resides in the fact that the force couplesFC-l, 2 do not involve the application of an end or axially aligned loadto the bearings 22a, b or 23a, [2, and this permits limited changes inthe overall length of the roll 21 due to operating condition changessuch as temperature changes. This arrangement also minimizes bearingwear.

It will be understood that modifications and variations may be effectedwithout departing from the spirit and scope of the novel concepts of thepresent invention.

I claim as my invention:

1. In a mounting for a roll whose axis is subject to deflection, saidroll having shaft elements at opposite ends thereof, in combination,allochiral pairs of bearings rotatably receiving said shaft elements andadapted to apply a force couple thereto, fixed pivots mounting each ofsaid pairs of bearings, allochiral lever arms rigid with each of saidpairs of bearings and extending therefrom to terminate adjacent theother of said pairs of bearings, and means for acting on the terminalportions of each of said lever arms to apply such force couple to saidshaft elements.

2. In a mounting for a roll whose axis is subject to de- 6 flection,said roll having shaft elements at opposite ends thereof, incombination, allochiral pairs of bearings rotatably receiving said shaftelements and adapted to apply a force couple thereto, fixed pivotsmounting each of said pairs of bearings, allochiral lever arms rigidwith each of said pairs of bearings and extending therefrom to terminateadjacent the other of said pairs of bearings,

and diaphragm means for acting on the terminal portions of each of saidlever arms to apply such force couple to said shaft elements.

3. In a mounting for a roll whose axis is subject to deflection, saidroll having shaft elements at opposite ends thereof, in combination,allochiral pairs of bearings rotatably receiving said shaft elements andadapted to apply a force couple thereto, fixed pivots mounting each ofsaid pairs of bearings, allochiral lever arms rigid with each of saidpairs of bearings and extending therefrom beneath the roll to terminateadjacent the other of said pairs of bearings, and means for acting onthe terminal portions of each of said lever arms to apply such forcecouple to said shaft elements.

4. In a mounting for a roll whose axis is subject to deflection, saidr-oll having shaft elements at opposite ends thereof, in combination,allochiral pairs of bearings rotatably receving said shaft elements andadapted to apply a force couple thereto, fixed pivots mounting each ofsaid pairs of bearings, allochiral lever arms rigid with each of saidpairs of bearings and extending therefrom beneath the roll to terminateadjacent the other of said pairs of bearings, and means for acting onthe terminal portions of each of said lever arms in a directiongenerally normal to the axis of said roll to apply such force couple tosaid shaft elements.

5. In combination, a roll whose axis is subject to deflection, said rollhaving shaft elements at opposite ends thereof, means applying a load tosaid roll tending to eflect deflection of the roll axis, allochiralpairs of bearings rotatably receiving said shaft elements and adapted toapply a force couple thereto, fixed pivots mounting each of said pairsof bearings, allochiral lever arms rigid with each of said pairs ofbearings and extending there from to terminate adjacent the other ofsaid pairs of bearings, and means for acting on the terminal portions ofeach of said lever arms to apply such force couple to said shaftelements.

6. In combination, a generally horizontally aligned roll whose axis issubject to deflection downwardly in the contral portion of the roll,means applying a load to the top of the roll tending to effect suchdeflection, allochiral pairs of bearings rotatably receiving said shaftelements and adapted to apply a force couple thereto, fixed pivotsmounting each of said pairs of bearings carrying the roll Weight andsuch load, allochiral lever arms rigid with each of said pairs ofbearings and extending therefrom beneath the roll to terminate adjacentthe other of said pairs of bearings, and means for acting on theterminal portions of each of said lever arms in a generally verticaldirection to apply such force couple to said shaft elements.

7. In a mounting for a roll whose axis is subject to deflection, saidroll having shaft elements at opposite ends thereof, in combination,allochiral pairs of bearings rotatably receiving said shaft elements andadapted to apply a force couple thereto, allochiral housing elementsrigid with and receiving each of said pairs of bearings and maintaininga spaced relation between the bearings of each pair, fixed pivotsmounting each of said housing elements, allochiral lever arms rigid witheach of the housing elements and extending therefrom to terminateadjacent the other of said pairs of bearings, and means for acting onthe terminal portions of each of said lever arms to apply such forcecouple to said shaft elements.

8. In combination, a roll whose axis is subject to deflection, said rollhaving shaft elements at opposite ends thereof, means applying a load tosaid roll tending to 8 effect deflection of the roll axis, allochiralpairs of bearpairs ofbearings, and means for acting on the terminal ingsrotatably receiving said shaft elements and adapted portions of each ofsaid lever arms to apply such force to apply a force couple thereto,allochiral housing elecouple to said shaft elements. ments rigid witheach of said pairs of bearings and maintaining a spaced relation betweenthe bearings of each 5 Refefelwes Cited in the file Of this patent pair,fixed pivots mounting each of said housing elements, UNITED STATESPATENTS allochiral lever arms rigid with each of said housing elementsand pairs of bearings contained therein and extend- 235-05952 Sept 1958ing therefrom to terminate adjacent the other of said 2897538 Shaplro eta1 1959

1. IN A MOUNTING FOR A ROLL WHOSE AXIS IS SUBJECT TO DEFLECTION, SAIDROLL HAVING SHAFT ELEMENTS AT OPPOSITE ENDS THEREOF, IN COMBINATION,ALLOCHIRAL PAIRS OF BEARINGS ROTATABLY RECEIVING SAID SHAFT ELEMENTS ANDADAPTED TO APPLY A FORCE COUPLE THERETO, FIXED PIVOTS MOUNTING EACH OFSAID PAIRS OF BEARINGS, ALLOCHIRAL LEVER ARMS RIGID WITH EACH OF SAIDPAIRS OF BEARINGS AND EXTENDING THEREFROM TO TERMINATE ADJACENT THEOTHER OF SAID PAIRS OF BEARINGS, AND MEANS FOR ACTING ON THE TERMINALPORTIONS OF EACH OF SAID LEVER ARMS TO APPLY SUCH FORCE COUPLE TO SAIDSHAFT ELEMENTS.